With the growth of Internet backbone bandwidth at a rate of about 50% per year, and the increase in broadband users (IPTV, video on demand, 3G services, etc.) and bandwidth-hungry applications, it has become a network operator to provide 100GE for business aggregation and core network applications 1. The urgent needs of large internet service providers. The 40G transmission system can no longer meet the current geometrically increasing bandwidth requirements. At present, some backbone networks with heavy data traffic have shown a trend of shortage of transmission bandwidth. 100G transmission technology has become the desired solution and is gradually being commercialized on a large scale. The WDM system has been facing a series of physical limitations from 2.5G to 10G and from 10G to 40G. The line rate is again increased to 100G, these physical constraints still exist, and the resulting transmission damage is more serious. The development of 100G technology is mainly to continuously overcome the influence of these factors. 1. Challenges faced by 100G transmission systems According to the development model of traditional wavelength division systems, 100G transmission systems will face many challenges such as higher system OSNR, higher dispersion tolerance and stronger nonlinear effects. 1. A higher system OSNR Wavelength division transmission systems use optical amplifiers to overcome fiber losses and extend the transmission distance of electroless relays. Optical amplifiers also introduce noise signals while power amplifying optical signals. On the other hand, when the baud rate increases, the optical receiver The bandwidth of the machine also needs to increase linearly with it, and the wider receiver bandwidth will allow higher power noise to enter the decision circuit of the receiver, which will cause an increase in the bit error rate, so the OSNR tolerance must be increased. 2. Require higher dispersion tolerance The dispersion effect of the optical signal in the optical fiber comes from the transmission speed of different frequency components in the spectrum of the modulated optical signal in the optical fiber, resulting in distortion of a series of optical pulses carrying service signals, resulting in inter-code between adjacent optical pulses Interference, resulting in bit errors. The dispersion tolerance of the transmitted optical signal is inversely proportional to the spectral width of the optical signal and at the same time proportional to the time domain width (pulse period) of the optical signal. For 100G signals, due to the increase in the baud rate of its optical signal, its spectral width will increase accordingly, and its time-domain waveform period will also decrease. If 100G also uses the traditional OOK / ASK modulation method (binary amplitude keying), Then the dispersion tolerance will be very small, and the existing DCM compensation method has been unable to meet the requirements. For 100G transmission, the problem of dispersion tolerance has become a serious problem, and the traditional optical dispersion compensation method can not overcome the harm caused by the reduction of dispersion tolerance. Newer compensation measures must be adopted to make 100G transmission possible. Like chromatic dispersion (CD), polarization mode dispersion (PMD) also limits the transmission capabilities of high-speed wavelength division systems. Polarization mode dispersion (PMD) refers to the same frequency. As long as the polarization mode is different, the fiber will also cause the propagation speed to be different. System cost. If 100G also uses the traditional OOK / ASK modulation method (binary amplitude keying), its PMD tolerance is less than 1ps, which cannot meet the project budget requirements. In 100G transmission systems, PMD tolerance is also considered to be a very serious problem. Conventional intensity modulation-direct detection (IM-DD) pattern modulation and reception methods cannot meet the system design requirements, and new technologies must be looked for solution. 3. Enhanced nonlinear effect of optical fiber The strength of the nonlinear effect of the optical fiber is related to the incoming optical power, the spectral width of the optical signal, the modulation pattern characteristics, the dispersion coefficient of the optical fiber, and the number of spans. The lower the degree. Some special pattern modulation techniques, such as phase modulation and RZ pattern modulation, are beneficial to enhance the resistance of the transmission pattern to the nonlinear effects of the fiber. 100G transmission system, if you want to overcome the worse nonlinear endurance caused by the increase in modulation rate, you must look for new breakthroughs in modulation technology. 50L Agriculture Drone,Agriculture Electric Sprayer Uav,Agriculture Sprayer Fertilizer Drone,Drone Sprayer Xuzhou Jitian Intelligent Equipment Co. Ltd , https://www.jitianequipment.com